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> Newbie question - elevation adjustment at 200 yd zero
Newbie question - elevation adjustment at 200 yd zero
@ 12:13 pm (GMT) |
Dennis MahonyMorning all,Looking for some advice/schooling. I am guessing that If I have a 200 yd zero and want to adjust a shot out to say, 300yds, would I only dial up 1/2 MOA to make up the 100yd difference? Bullet/cartriddge ballistics notwithstanding... Kind regards, Dennis |
Replies
@ 07:30 am (GMT) |
Nathan FosterRe: Newbie question - elevation adjustment at 200 yd zeroHi Dennis, zero distance is these days a bit of an issue as people become less familiar with their kit. In the past, hunters set their zero at 200 to 270 yards depending on the cartridge, then applied an appropriate hold over to what they guessed was 300 yards (no range finders back then).Generally speaking, there were two basic camps. Those who hunted woods and out to moderate ranges only, would adopt a 200 yard zero as shown on packets of ammunition. Those who hunted open country adopted Jack O'Connors 3" rule which for the .270 Win (eg. Rem 130gr Core-Lokt MV 2900fps), was roughly 3" high at 100 yards, zero at around 270 yards and 3" low at 300 yards. 3" is the width of a mans fingers so it is very easy to visualize. The trajectories shown on this website, at the bottom of each article are mostly based around the 3" method to help hunters get the most of of their cartridges. A slight hold under center provides suitable compensation for 100 yard shots while a slight hold above center is adequate for "I reckon its about 300". Nowadays and using range finders, it has become common place to zero at 100 yards. The hunter may use a holdover reticle, use a quick dial Leupold turret or regular dial turret when attempting a 300 yard shot. Unfortunately, the apparent precision and or speed of these systems does not translate into reality in the field. In New Zealand at least, by the time the hunter takes a range reading, gets into position and then either dials or uses a hold over reticle, game animals are quite often gone before the hunter gets his shot away due to wind currents (scent) eddying in valleys. I have seen this time and again when guiding. Much of course depends on the game species and terrain. The trouble is, if you become used to hunting docile game in kind winds, it can all come apart later during more challenging game hunts. Confidence in the 3 inch rule allows one to get a shot away very quickly and with acceptable accuracy, though it is helpful if you have a range finder, to take an initial reading across valleys etc to obtain a general idea of the lay of the land. Regarding your 200 yard zero. Using the .308 as an example and without taking any particular brand of ammo into account or speeds, if you were to sight in dead on at 200 yards, bullet drop would be about 8 or 9" at 300 yards and you would need to come up 2.5 to 3 MOA in order to be dead on. Using the 3" rule, the rifle prints 3" high at 100, dead on at around 240 to 250 yards, 3" low at around 280 and 5" to 6" low (fingers of two hands) at 300 yards (aim at spine). It really comes down to the type of game you hunt, expected ranges and the habits you wish to build. You can of course mix things up. You can for example sight 3" high at 100 yards but still dial for a precise shot at 300 yards - if conditions allow. On the other hand, a person who mostly neck shoots game out to moderate ranges only using a .223 or .243 might instead prefer a 200 yard zero to avoid the need for hold under. The key factor is having confidence in your kit through practice. Unfortunately, many hunters now lack the confidence to hold slightly under or over, nor the ability to factor in any extra compensation for uphill or downhill shots. This is compounded by the marketing of technology to supposedly make shooting easier. It doesn't, it just robs you of your own ability to problem solve and make quick decisions. It was for this precise reason that I wrote the tactical tomfoolery article. https://www.ballisticstudies.com/Knowledgebase/tacticaltomfoolery.html OK, hope that helps explain the ins and outs a little bit. All the best. |
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@ 03:16 pm (GMT) |
Dennis MahonyRe: Newbie question - elevation adjustment at 200 yd zeroThank you Nathan for your generosity in sharing some knowledge. This is quite helpful for me and clears things up alot.Kind regards, Dennis |
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